Vortex formation of cardiac bilateral ventricles in fetuses with tetralogy of fallot assessed by blood speckle-tracking echocardiography

To analyze the vortex characteristics of the cardiac bilateral ventricles in fetuses with tetralogy of Fallot (TOF) using a high–frame rate ultrasound with blood speckle-tracking (BST). A prospective cross-sectional study of 35 fetuses with TOF and 35 gestational age-matched controls was conducted. Fetuses with TOF were classified as mild to moderate TOF or severe TOF based on pulmonary annular diameter z-scores. The number, position, length, width, area and duration of the vortex in the bilateral ventricles were recorded by BST echocardiography. Correlations between the vortex characteristics and cardiac morphology parameters, as well as ventricular function, were assessed in fetuses with TOF. The fetuses with TOF exhibited larger and longer duration vortex in the right ventricle (RV) than that of the controls (all P < 0.05). Linear regression analysis demonstrated that vortex area of RV was positively related to sphericity index (SI) of RV, isovolumic relaxation time (IRT) and myocardial performance index of RV in the fetuses with TOF (all P < 0.001). In fetuses with severe TOF, The vortex in RV was located closer to the cardiac apex and the vortex in the left ventricle (LV) was larger than that in normal fetuses (all P < 0.05). Vortex area of LV only in fetuses with severe TOF was slightly positively correlated with LV-IRT (P = 0.038). The fetuses with TOF exhibited special vortex characteristics in RV, and some vortex characteristics, especially vortex area in RV, were closely related to RV anatomical and functional abnormalities. Further study is needed to explore the diagnostic and prognostic value of vortex characteristics in fetuses with congenital heart disease.